OneFolder exits image view when new files are detected in the background

[cspius]

Describe the bug
When new images are added to a OneFolder-managed directory in the background, OneFolder interrupts the current image view and jumps back to the overview/grid while an image is open.

To Reproduce
Steps to reproduce the behavior:
1. Open OneFolder on macOS
2. Open a folder containing images
3. Open a single image (detail view)
4. While the image is open, add new images to the same directory in the background (e.g. via Syncthing or Finder copy)
5. Observe OneFolder’s behavior when it detects the new files

Expected behavior
When new images are added to the directory, OneFolder should update the library in the background without interrupting the currently opened image. The image view should remain open and stable.

Actual behavior
As soon as OneFolder detects new images in the directory, it automatically exits the image view and jumps back to the folder overview/grid.

OneFolder version v1.1.2
Desktop OS macOS Tahoe 26.2

Additional context
• This happens while OneFolder is actively monitoring the folder for new files
• The issue is especially noticeable when using background sync tools (e.g. Syncthing) that add images incrementally
• The behavior disrupts reviewing or inspecting images while synchronization is in progress
• A background re-index or incremental update should not reset the current UI state